public static function get_instance()
 {
     if (!self::$instance) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 /**
  * Initialize the plugin and its dependencies.
  *
  * Initialize the plugin and its dependencies.
  *
  * @since 1.0.0
  * @access public
  * @see __construct
  * @internal Uses plugins_loaded action
  *
  */
 public function plugins_loaded()
 {
     $GLOBALS['pms_post_protected'] = false;
     $GLOBALS['pms_session'] = Postmatic_Social_Comments_Session::get_instance();
     $GLOBALS['postmatic-social'] = new Postmatic_Social_Comments_Plugin(array('wordpress', 'gplus', 'twitter', 'facebook'));
     add_filter('pre_comment_author_email', array($this, 'twitter_author'));
     //Add settings link to plugins screen
     $prefix = is_multisite() ? 'network_admin_' : '';
     add_action($prefix . 'plugin_action_links_' . Postmatic_Social::get_plugin_basename(), array($this, 'plugin_settings_link'));
 }